So after I first discovered my tailbiter actually WAS a tailbiter, I found there are weird little white dots on just his left pectoral fin. They've been there for a while now, and he tends to clamp that fin. However, even after multiple treatments of AQ salt (They've been there for 3+ months but haven't spread which makes me think they aren't ick) they aren't going away. What COULD they be if not ick?

No, sadly. He never stays still for me when I have a camera out. It's not only one single dot, but a cluster of 4 little dots ON the pectoral fin. I know the lymphocysts aren't fuzzy, but don't they start under scales, not on fins?